nxdir:selectOneListbox tag ignores notDisplayDefaultOption

1. The nxdir:selectOneListbox tag is used in ./nxserver/nuxeo.war/create_relation.xhtml:

         <h:panelGroup>
           <nxdir:selectOneListbox value="#{relationActions.predicateUri}"
             directoryName="predicates" id="predicateUri" required="true"
             localize="true" />
           <h:message for="predicateUri" class="errorMessage" />
         </h:panelGroup>
   

2. Modifying this into:

         <h:panelGroup>
           <nxdir:selectOneListbox value="#{relationActions.predicateUri}"
             directoryName="predicates" id="predicateUri" required="true"
             localize="true" size="1" notDisplayDefaultOption="false" />
           <h:message for="predicateUri" class="errorMessage" />
         </h:panelGroup>
   

   In 5.8 one can see the combobox displaying the default option (see goodBehavior.png) but from 6.0 and later versions it does not (see badBehavior.png). Even forcing the defaultoption to be displayed with notDisplayDefaultOption="false" does not work and selects the first value of the list.

It seems there was some changes between 5.8 and 6.0 for this tag and some classes were created for legacy.